Process for producing negative copies

Abstract

A process for producing negative copies is disclosed in which a light-sensitive or radiation-sensitive recording material comprising a layer support and a normally positive-working light-sensitive or radiation-sensitive layer applied thereto is irradiated imagewise, thermally treated, irradiated overall and then developed with an alkaline developer. Thermal treatment is carried out with water or with an aqueous solution, at temperatures in the range from about 50° to 100° C., preferably from 60° to 90° C., within a period of time varying between about 1 second and 5 minutes, preferably between 5 seconds and 1 minute, overall irradiation is performed on the optionally still hot recording material and development is thereafter carried out within a period of time varying between about 10 seconds and 2 minutes, preferably between 15 seconds and 1 minute. The process can be carried out according to the customary procedure known in the practice of positive processing, and results in perfect printing stencils.

What is claimed is: 
     
       1. A process for producing negative copies from a light-sensitive or radiation-sensitive recording material comprising a layer support and a normally positive-working light-sensitive or radiation-sensitive layer applied thereto which contains at least one of: a 1,2-quinone diazide, and   a mixture of a component forming a strong acid under the action of actinic radiation and a compound having at least one acid-cleavable C--O--C group, the process comprising the steps of:   imagewise irradiating the layer;   thermally treating the imagewise-irradiated layer with water or an aqueous solution, at temperatures in the range from about 50° to 100° C., for a period of time between about 1 second and 5 minutes;   beginning overall irradiation of the layer without allowing the layer to cool;   overall irradiating the layer to produce a negative latent image; and then   developing the layer with an alkaline developer for a period of time between about 10 seconds and 2 minutes to produce a negative image.   
     
     
       2. The process as claimed in claim 1, wherein thermal treatment is carried out using an aqueous solution containing at least one surface-active substance. 
     
     
       3. The process as claimed in claim 1, wherein the aqueous solution has a pH varying from 5 to 8. 
     
     
       4. The process as claimed in claim 1, wherein the aqueous solution is buffered in the pH range from 5 to 8. 
     
     
       5. The process as claimed in claim 1, wherein the aqueous solution contains a complexing agent. 
     
     
       6. The process as claimed in claim 1, wherein the aqueous solution contains an additive to increase heat conductivity. 
     
     
       7. The process as claimed in claim 1, wherein the aqueous solution contains a defoamer. 
     
     
       8. The process as claimed in claim 1, wherein the aqueous solution contains an additive to increase viscosity. 
     
     
       9. The process as claimed in claim 1, wherein development is carried out for a period of time between about 15 seconds and 1 minute. 
     
     
       10. The process as claimed in claim 1, wherein thermal treatment is carried out in the temperature range from about 60° to 90° C. 
     
     
       11. The process as claimed in claim 10, wherein thermal treatment is carried out for a period of time between about 5 seconds and 1 minute. 
     
     
       12. The process as claimed in claim 1, wherein thermal treatment is carried out for a period of time between about 5 seconds and 1 minute.